In my book, high value SC would be that very same Zegna in the $500-$1000 range

Now, really depends on many things: your location (availability of outlets with large discounts), which Zegna line are we talking about, etc, etc... If it is a mainline Zegna, I wouldn't consider $2000 much of a discount. I personally do not have experience with Zegna, but brands of similar quality/price such as Pal Zileri, Corneliani etc, I was able to find great stuff (suits and jackets) in the above mentioned price range. Even better stuff from makers such as Belvest, Caruso etc.

Assuming you don't have access to B&M outlets, ebay is a good place (usually there is a good description of the item in terms of dimensions), yoox also (a bit of a crap shot, but good return policy). The key is to know what you like, what fits you and what are your measurements.

Virtual Clothes Horse, Shop the Finest, B&S here on SF are all good bets. Saks off Fifth, NM Last Call. Sierra Trading Post carries Isaia, believe it or not. If you want to stretch to bespoke, I have used Jonathan Behr in LA and his bespoke SCs are probably a little less than $2000 (depending on fabric) and they are full bespoke. I (and my father) have lots of stuff from him and he's awesome.

If you can deal with things being slightly worn but in excellent condition, best way to do this is to start following the Luxeswap thread and checking out @SpooPoker and his offerings. some excellent stuff there.

Check out ehaberdasher, he has his own line of suits and sportcoats. If you can find your size and colour you're not going to find much better value for your dollar. He's also doing preorders on a run of sportcoats right now.

Now would actually be a great time to check Neiman Marcus for sales on blazers. I think they're going to be shifting inventory soon for Spring

It seems like he wants a zegna in the 500 dollar range - that only happens at outlet / discount stores. Even Neimans Marcus's First Call sale does not get marked down THAT much - its usually like 3000 down to 2000 or 1500 or 1000 at best.